An evaluation of exhaled flow measuring mouthpieces for breath sampling devices

摘要

A study is conducted to determine the dimensions of an exhaled flow measuring mouthpiece for a breath-sampling device that requires breathing for an extended period of time. Fleisch, Pitot and Venturi type differential pressure based flow measuring mouthpieces of various dimensions are evaluated. Inner diameters (IDs) of the cylinder shaped Fleisch, Pitot and Venturi mouthpieces are varied from 5mm to 25mm. Based on the study, we conclude IDs ranging from 8.75mm to 12.5mm for Fleisch type, IDs ranging from 10mm to 12.5mm for Pitot type and ID of 10mm for Venturi type are the most suitable dimensions for a breath sampling device.